Cell-cycle control linked to extracellular environment by MAP kinase pathway in fission yeast.
In fission yeast the onset of mitosis is brought about by Cdc2/Cdc13 kinase, which is inhibited by the Wee1/Mik1 tyrosine kinases and activated by Cdc25 tyrosine phosphatase. This control network integrates many signals, including those that monitor DNA replication, DNA damage and cell size. We report here that a fission ... yeast MAP kinase pathway links the cell-cycle G2/M control with changes in the extracellular environment that affect cell physiology. Fission yeast spc1- mutants have a G2 delay that is greatly exacerbated by growth in high osmolarity media and nutrient limitation. A lethal interaction of spc1 and cdc25 mutations shows that Spc1 promotes the onset of mitosis. Spc1 is a MAP kinase homologue that is activated by Wis1 kinase in response to osmotic stress and nutrient limitation. Spc1 is inactivated by Pyp1, a phosphatase previously identified as a mitotic inhibitor. Pyp1 dephosphorylates only tyrosine-173 of Spc1, unlike the dual-specificity phosphatases that have been shown to regulate other MAP kinases.
Mesh Terms:
Amino Acid Sequence, Animals, Base Sequence, Calcium-Calmodulin-Dependent Protein Kinases, Cell Cycle, Cell Cycle Proteins, Cloning, Molecular, DNA Primers, Mitogen-Activated Protein Kinases, Molecular Sequence Data, Mutation, Phosphorylation, Protein Tyrosine Phosphatases, Schizosaccharomyces, Schizosaccharomyces pombe Proteins, Sequence Homology, Amino Acid, Tyrosine
Amino Acid Sequence, Animals, Base Sequence, Calcium-Calmodulin-Dependent Protein Kinases, Cell Cycle, Cell Cycle Proteins, Cloning, Molecular, DNA Primers, Mitogen-Activated Protein Kinases, Molecular Sequence Data, Mutation, Phosphorylation, Protein Tyrosine Phosphatases, Schizosaccharomyces, Schizosaccharomyces pombe Proteins, Sequence Homology, Amino Acid, Tyrosine
Nature
Date: Dec. 14, 1995
PubMed ID: 7501024
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